The Multipurpose Arthritis and Musculoskeletal Diseases Center at Northwestern University (NU) is an interdisciplinary program that operates as an integrated unit to address a broad range of clinical, research and educational activities. The programs in the center integrate all 3 campuses of NU, Medical School, Evanston, and Children's Memorial Medical Center. The current biomedical research component activities can be divided in the broad programmatic themes of Immunobiology, Cellular Molecular Biology, and Musculoskeletal Structure and Function. The Biomedical development and feasibility (D/F) studies included in this proposal will search for novel B cell hyperactivity genes, define the mechanism of association between the protein tyrosine kinases hck and lyn with high affinity IgG receptor (FcgammaRI), and examine superantigen interactions with MHC II molecules to test the hypothesis that peptides in the antigen binding site may influence the binding of both SSA and SEB. The education, epidemiology and health services component (EEHSR) of the Center employs a broad-based multidisciplinary approach to address problems in pediatric and adult populations. Special emphasis is given to the epidemiology of osteoarthritis, rheumatoid arthritis, systemic lupus erythematosus and juvenile dermatomyositis. Economics, outcomes and decision analysis are strongly represented. The EEHSR projects presented in this grant will define the importance of and factors responsible for osteoporosis in patients with lupus, examine the contribution of neuromechanical factors to the progression of osteoarthritis, and determine the importance of rehabilitation to outcomes in rheumatoid arthritis. A D&F proposal would create and assess an intervention to prevent function limitation in elderly patients with osteoarthritis. A Methodology and Data Management Core is proposed to support all EEHSR projects.